For many types of products, customizable appearance of the product may be desirable. For example, it may be attractive to be able to customize the appearance of at least a part of a product depending on its current state, to convey information about the current state of the product to a user in an intuitive and attractive way. It may also be perceived as attractive to the user of a product to be able to alter its appearance to reflect the user's personality or mood etc.
According to one well-known example, such customizable appearance of a product is realized by exchangeable “skins” on consumer electronic products, such as mobile telephones. This type of “skins” is typically provided as plastic shells that can be exchanged by the user of the product.
It has also been suggested to use electrically controllable optical properties of an appearance-modifying device covering a surface of a product to alter the appearance of the product.
US 2004/0189591 discloses one example of such an appearance-modifying device in the form of electrophoretic display devices covering control buttons of a programmable remote control unit. Depending on the component to be controlled through the programmable remote control unit, the electrophoretic display devices are adjusted to display the settings relevant to the particular component to be controlled.
The appearance-modifying device disclosed in US 2004/0189591 is provided in the form of microcapsules sandwiched between top and bottom electrode layers. Each microcapsule contains positively charged white pigment chips and negatively charged black pigment chips suspended in a clear suspension medium. By forming a suitable electric field pattern in the appearance-modifying device of US 2004/0189591, a black and white image can be formed, which is thus attributed to the respective button.
Although enabling modification of the appearance of a product, more specifically a programmable remote control, the appearance-modifying device disclosed in US 2004/0189591 is not suitable for every application. In particular, the type of appearance-modifying device described above cannot be used when the surface covered thereby itself conveys information. For example, at least a portion of the surface may be a display that is only sometimes active, but then must be clearly visible to the user of the product. Further, the appearance-modifying device of US 2004/0189591 requires a relatively high drive voltage, typically between 5-15V.